AC_PrecLand: use enum-class for EstimatorType

And remove accessor for same

libraries/AC_PrecLand/AC_PrecLand.cpp

@@ -279,8 +279,8 @@ void AC_PrecLand::run_estimator(float rangefinder_alt_m, bool rangefinder_alt_va
 {
     const struct inertial_data_frame_s *inertial_data_delayed = (*_inertial_history)[0];
 
-    switch (_estimator_type) {
-        case ESTIMATOR_TYPE_RAW_SENSOR: {
+    switch ((EstimatorType)_estimator_type.get()) {
+        case EstimatorType::RAW_SENSOR: {
             // Return if there's any invalid velocity data
             for (uint8_t i=0; i<_inertial_history->available(); i++) {
                 const struct inertial_data_frame_s *inertial_data = (*_inertial_history)[i];
@@ -315,7 +315,7 @@ void AC_PrecLand::run_estimator(float rangefinder_alt_m, bool rangefinder_alt_va
             }
             break;
         }
-        case ESTIMATOR_TYPE_KALMAN_FILTER: {
+        case EstimatorType::KALMAN_FILTER: {
             // Predict
             if (target_acquired()) {
                 const float& dt = inertial_data_delayed->dt;
@@ -490,7 +490,7 @@ void AC_PrecLand::Write_Precland()
         meas_z          : target_pos_meas.z,
         last_meas       : last_backend_los_meas_ms(),
         ekf_outcount    : ekf_outlier_count(),
-        estimator       : estimator_type()
+        estimator       : (uint8_t)_estimator_type
     };
     AP::logger().WriteBlock(&pkt, sizeof(pkt));
 }

libraries/AC_PrecLand/AC_PrecLand.h

@@ -61,9 +61,6 @@ public:
     // returns time of last time target was seen
     uint32_t last_backend_los_meas_ms() const { return _last_backend_los_meas_ms; }
 
-    // returns estimator type
-    uint8_t estimator_type() const { return _estimator_type; }
-
     // returns ekf outlier count
     uint32_t ekf_outlier_count() const { return _outlier_reject_count; }
 
@@ -92,9 +89,9 @@ public:
     static const struct AP_Param::GroupInfo var_info[];
 
 private:
-    enum estimator_type_t {
-        ESTIMATOR_TYPE_RAW_SENSOR = 0,
-        ESTIMATOR_TYPE_KALMAN_FILTER = 1
+    enum class EstimatorType : uint8_t {
+        RAW_SENSOR = 0,
+        KALMAN_FILTER = 1,
     };
 
     // returns enabled parameter as an behaviour
@@ -117,7 +114,7 @@ private:
     AP_Int8                     _enabled;           // enabled/disabled and behaviour
     AP_Int8                     _type;              // precision landing sensor type
     AP_Int8                     _bus;               // which sensor bus
-    AP_Int8                     _estimator_type;    // precision landing estimator type
+    AP_Enum<EstimatorType>      _estimator_type;    // precision landing estimator type
     AP_Float                    _lag;               // sensor lag in seconds
     AP_Float                    _yaw_align;         // Yaw angle from body x-axis to sensor x-axis.
     AP_Float                    _land_ofs_cm_x;     // Desired landing position of the camera forward of the target in vehicle body frame